Exodus 23:20

Three gracious promises are here made to Israel, to engage them to their duty and encourage them in it; and each of the promises has some needful precepts and cautions joined to it. I. It is here promised that they should be guided and kept in their way through the wilderness to the land of promise: Behold, I send an angel before thee (Exo 23:20), my angel (Exo 23:23), a created angel, say some, a minister of God's providence, employed in conducting and protecting the camp of Israel; that it might appear that God took a particular care of them, he appointed one of his chief servants to make it his business to attend them, and see that they wanted for nothing. Others suppose it to be the Son of God, the angel of the covenant; for the Israelites in the wilderness are said to tempt Christ; and we may as well suppose him God's messenger, and the church's Redeemer, before his incarnation, as the Lamb slain from the foundation of the world. And we may the rather think he was pleased to undertake the deliverance and guidance of Israel because they were typical of his great undertaking. It is promised that this blessed angel should keep them in the way, though it lay through a wilderness first, and afterwards through their enemies' country; thus God's spiritual Israel shall be kept through the wilderness of this earth, and from the insults of the gates of hell.

— Matthew Henry's Concise Commentary (public domain)

Behold, I send an Angel before thee, to keep thee in the way--The communication of these laws, made to Moses and by him rehearsed to the people, was concluded by the addition of many animating promises, intermingled with several solemn warnings that lapses into sin and idolatry would not be tolerated or passed with impunity.

— Jamieson-Fausset-Brown Commentary (public domain)